On one night in December 2015, more rain fell over Cumbria than ever recorded before, and 600 farms across the county took a battering: livestock drowned, fencing was destroyed and tons of gravel ended up on fields resulting in hefty repair bills.
But while nearby bridges collapsed and the army was called out to help people flooded out of their homes, one farm was fine. The previous year the farmer had been persuaded to take part in an experimental project with a nearby paper mill, which involved planting 28 acres of willow crop, which saved his land.
The paper mill had just invested £108m in a biomass plant. Keen to move away from fossil fuels, they needed a sustainable source of wood chips for fuel. To keep their carbon footprint low, they looked local. A study concluded that will trees would be the best energy crop: quick to grow (6 inches in a week is not unusual) and don't have especially deep roots (a concern for farmers trying to grow other crops nearby).
After the 2015 deluge, there were islands of stones and railway sleepers in his fields but they had all been stopped by the willow. Planted the previous year, the willow wasn't yet ready for harvesting, but had slowed the flow by intercepting rain and impeding the flow of water over ground and soil. While the paper mill's focus was on feeding the biomass plant, willow's role as a flood barrier was a happy byproduct.
Farmers earn good prices per acre per year selling the harvested willow; a real boon in the increasingly marginal business of farming. It costs £1.20 to sheer a sheep but the going price of a fleece is just 20p. Income from growing willow means farmers are less reliant on subsidies.
The owner of the only working slate mine in England with land available but needing a low maintenance crop, also signed up to grow willow. She sees the new crop as performing a community service role, catching debris before it hits the town and slowing the speed of water on the flood plain. It also makes the land more productive and is more ecological, with increased biodiversity brought by the willow, which has the potential to attract 266 insect species, including 173 types of moths and 51 different types of beetle. Insects such as bees and overwintering butterflies also use the willow catkins as an early season nectar source.
Source: Flood defences: how willow proved to be a natural defender by Helen Pidd in The Guardian, 30 Dec. 2018.
